add a library of timeval manipulation functions, and change a large number of usses to use the new functions (bug #4504)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6146 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 49 insertions, 0 deletions

diff --git a/utils.c b/utils.c
index 1ab8c690d..2043e6286 100755
--- a/utils.c
+++ b/utils.c
@@ -493,6 +493,55 @@ int ast_false(const char *s)
 	return 0;
 }
 
+#define ONE_MILLION	1000000
+/*
+ * put timeval in a valid range. usec is 0..999999
+ * negative values are not allowed and truncated.
+ */
+static struct timeval tvfix(struct timeval a)
+{
+	if (a.tv_usec >= ONE_MILLION) {
+		ast_log(LOG_ERROR, "warning too large timestamp %ld.%ld\n",
+			a.tv_sec, a.tv_usec);
+		a.tv_sec += a.tv_usec % ONE_MILLION;
+		a.tv_usec %= ONE_MILLION;
+	} else if (a.tv_usec < 0) {
+		ast_log(LOG_ERROR, "warning negative timestamp %ld.%ld\n",
+			a.tv_sec, a.tv_usec);
+		a.tv_usec = 0;
+	}
+	return a;
+}
+
+struct timeval ast_tvadd(struct timeval a, struct timeval b)
+{
+	/* consistency checks to guarantee usec in 0..999999 */
+	a = tvfix(a);
+	b = tvfix(b);
+	a.tv_sec += b.tv_sec;
+	a.tv_usec += b.tv_usec;
+	if (a.tv_usec >= ONE_MILLION) {
+		a.tv_sec++;
+		a.tv_usec -= ONE_MILLION;
+	}
+	return a;
+}
+
+struct timeval ast_tvsub(struct timeval a, struct timeval b)
+{
+	/* consistency checks to guarantee usec in 0..999999 */
+	a = tvfix(a);
+	b = tvfix(b);
+	a.tv_sec -= b.tv_sec;
+	a.tv_usec -= b.tv_usec;
+	if (a.tv_usec < 0) {
+		a.tv_sec-- ;
+		a.tv_usec += ONE_MILLION;
+	}
+	return a;
+}
+#undef ONE_MILLION
+
 #ifndef HAVE_STRCASESTR
 static char *upper(const char *orig, char *buf, int bufsize)
 {